1. Field of the Invention
The present invention relates to antennas and communication systems. More specifically, the present invention relates to electronically scanned phased array antennas and communication systems in which such antennas are used.
2. Description of the Related Art
The requirements for portable personal communication systems, particularly for military applications, continue to increase over time. From World War II to the Viet Nam war, the need was met by a communication system carried by a soldier, i.e. a ‘radio man’ with a large backpack. These systems typically required a large antenna and forced many tradeoffs in performance, weight, compactness, and reliability.
Current and future military requirements have forced the communication systems to evolve and to a considerable extent, radio systems developers have responded. However, the antenna has not evolved. Consequently, the antenna remains large and, inasmuch as these antennas are typically implemented as a dipole or a monopole antenna, these antennas do not allow for the directional control needed for high-performance in other applications.
For example, soldiers typically require a compact, non-intrusive means to carry an antenna to communicate. Antennas carried by soldiers are generally omni-directional antennas or do not provide any electronic steering to provide gain. Most current instances of soldier-carried antennas are monopole or dipole antennas mounted on radios inside backpacks. Soldier-carried directional antennas are typically dishes that must be mounted on a stationary surface and cannot operate while the soldier is moving or walking. Recent advances have made miniature patch or spiral antennas embedded in bulletproof vests worn by soldiers, but such antennas do not have electronic beam-steering capabilities. Other proposals have had patch antennas embedded inside helmets, but these proposed antennas, while having some gain, do not offer electronic beam steering capabilities.
Thus, a need remains in the art for a system or method for improving the performance of conventional portable personal communication systems.